Fluidic control apparatus for fuel injection systems

ABSTRACT

A fluidic controlled fuel injection system for internal combustion engines comprises an engine speed sensor and a sensor for monitoring the mass flow of air into the intake manifold. The sensors provide digitized fluidic inputs to fluidic logic circuits for deriving phased fluidic load signals utilized to control various fuel injection valves.

United States Patent mi Husted Oct. 23, 1973 [54] FLUlDlC CONTROLAPPARATUS FOR 3,6l6,782 ll/l97l Matsui et al. 123/119 R FUEL-INJECTIONSYSTEMS 3,672,339 6/1972 Lazar l23/DlG. 10

[75] inventor: Royce H. Husted, Wheaton, ill. [73] Assignee: AutomaticSwitch 0)., Florham Primary Bums Attorney-Breitenfeld & Levine Park, NJ.

[22] Filed: Aug. 23, 1971 [21] Appl. No.: 173,870 ABSTRACT 123/119123/103 123/139 A fluidic controlled fuel injection system for internall l0 combustion engines comprises an engine speed sensor F02! FOZm 39/00and a sensor for monitoring the mass flow of air into Field of Search139 the intake manifold. The sensors provide digitized flu- 123/119 103103 B idic inputs to fluidic logic circuits for deriving phased fluidicload signals utilized to control various fuel in- [56] References Citedj tion valves.

UNITED STATES PATENTS 3,556,063 1/197-1 Tuzson 123/103 R 19 Claims, 2Drawing Figures 54 r" g fl w m w L fl s m 1 l i M 82 ENGINE 5a tggg- Ismear) e0 SENSDR 62 ea 1 FLUIDIC LOGIC 79 fh FUEL 68 7e 7 1p pumn 7eFLUlDlC r i i l MASS LOGIC 1 96/94 INTERNAL 9 99] AIR COBLBJEEON FLOW 810 7 E SENSOR FLUIDIC LOGIC FLUIDIC CONTROL APPARATUS FOR FUEL INJECTIONSYSTEMS BACKGROUND OF THE INVENTION The present invention relates tofuel injection systems for internal. combustion engines, and moreparticularly to a novel approach for controlling fuel injection systems.

Improper carburetion is a significant factor contributing to airpollution by internal combustion engines. Improper fuel-air mixturesproduce inefficient operation and, in many cases, an incomplete or totalabsence of combustion with'the resulting discharge of uncombusted fuelinto the atmosphere.

The carburetor is most widely used for controlling the fuel-air mixturein internal combustion engines. Despite their wide use, carburetors arenot capable of precise control of the fuelair mixture or ratio'for allengine operating conditions. Thus, matching carburetion to engine speedis largely a matter of compromise. Moreover, carburetors, in time, fallout of adjustment and are easily fouled.

Fuel injection systems are well known and are capable of more accuratelyand reliably controlling the fuelair mixture. However such systems areconsiderably more expensive than carburetors and thus their use has beenlimited to large engines or high performance, special purposeengineswhere the additional expense can be justified. A significant portion ofthe expense of fuel injection systems resides in the apparatus forcontrolling the fuel injection valves. 7

It is accordingly an object of the present invention to provide animproved fuel injection system for internal combustion engines.

An additional object is to provide a fluidic control for fuel injectionsystems.

Still another object is to provide a fluidic control of the abovecharacter, which is efficient and reliable in operation, and yet isinexpensive to manufacture.

Other objects of the invention will in part be obvious and in partappear hereinafter.

SUMMARY OF THE INVENTION Further in accordance with the invention, theengine speed sensor synchronizes the timing of the load signal pulsesrelative to each engine cycle such that the fuel is injected at theproper time.

For multi-cylinderinternal combustion engines, the sensor outputs areapplied to plural fluidic logic circuits to derive discrete fluidic loadsignals to separate fuel injection valves associated with the variousengine cylinders. To accommodate the fact that the reciprocations of thepistons in the various cylinders are relatively phased, the fluidicoutput signals of the engine speed sensor supplied to the variousfluidic logic circuits are correspondingly time phased.- As aconsequence, the resulting load signal pulses are also appropriatelyphased in time, in order that fuel injection for a particular cylinderis initiated at the proper time during the reciprocation cycle of thepiston therein, as well These digitized fluidic output signals areprocessed in fluidic logic circuitry to derive a fluidic signalproportional to engine load for controlling a fuel injection valve toadmit a determined amount of fuel.

More specifically, the digitized sensor output signals are processed bythe fluidic logic to, in effect, enter a theoretically optimum loadcurve for the internal combustion engine on the basis of the prevailingengine speed and prevailing mass air flow into the intake manifold,pursuant to deriving the appropriate load signal. The informationalaspect of the load signal is, in accordance with the present invention,its pulse duration which is utilized to control the duration the fuelinjection valve is opened and thus the amount of fuel injected.

as for the appropriate time duration.

The invention accordingly comprises the features of construction,combination of elements and arrangements of parts which will beexemplified in the construction hereinafter set forth, and the scope ofthe invention will be indicated in the claims.

For a fuller understanding of thenature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings, in which:

FIG. 1 is a block-diagram of a fluidic controlled fuel injection systemillustrating the principles of the present invention; and I FIG. 2 is adetailed fluidic logic and schematic diagram illustrating a specificembodiment of the invention.

Like reference numerals refer to corresponding parts throughout theseveral views of the drawings.

DETAILED DESCRIPTION The apparatus of the invention is generallyillustrated in FIG. 1 as including anengine speed sensor, generallyindicated at 50, which is mechanically linked to an internal combustionengine 52, asrepresented by the dash line 54, to monitor engine RPM. Theinternal combustion engine is assumed to be a four cylinder engine,however, it will be apparent from the description to follow that theapparatus of the present invention can readily be adapted to control afuel injection system for an engine having any number of cylinders.

The engine speed sensor 50 develops fluidic outputs, indicative ofengine speed, which are supplied via fluidic connections 56, 58, 60 and62 to separate, but identically constructed, fluidic logic circuits 64,66, 68 and 70. As will be seen, sensor 50 may also be considered as acrank angle sensor. A sensor 72 is coupled by a fluid connection 74 tothe throat of a venturi section 76, included in'the input end of anintake manifold 78 for the internal combustion engine, to monitor themass flow, i.e., velocity, of air into the intake manifold, as

- controlled by throttle 79. This mass air flow sensor provides afluidic output, representative of mass air flow, for application overfluidic connection 80 to each of the fluidic logic circuits 64, 66, 68and 70. The fluidic outputs from sensors 50 and 72 are processed by thevarious fluidic logic circuits to derive separate load signals,indicative of the engine load, which are supplied over individualfluidic connections 82, 84, 86 and 88 to control respective fuelinjection valves 90, 92, 94 and 96. These injection valves admit adetermined amount of fuel supplied thereto under constant pressure by afuel pump 98 via a fluid connection 100.

As is well known,thc reciprocation cycles of the pistons in a fourcylinder engine are phased 90 apart, and thus the load signals derivedby the four fluidic logic circuits must be correspondingly time phased,such that fuel is injected at the appropriate time in the reciprocationcycle of each piston. As will be seen from FIG. 2, appropriate phasingof the load signals is controlled by the engine speedsensor 50, which iseffectively synchronized to the operating cycles of the various pistons.It will be appreciated that the invention is applicable to internalcombustion engines having any number of cylinders. 7

As will be seen more clearly from FIG. 2, the fluidic outputs from theengine speed sensor 50 and from the mass air flow sensor 72 consist ofplural, digitized fluidic output signals which are processed by thevarious fluidic logic circuits to effectively enter a theoreticallyoptimum load curve for the particular internal combustion engine on thebasis of the prevailing engine speed and the prevailing mass air flowinto the intake manifold, pursuant to deriving phased fluidic loadsignals for controlling the various fuel injection valves. Specifically,the load signals are in the form of fluidic signal pulses which areproperly timed relative to engine speed and are of appropriate durationsto control the open time interval for the various fuel injection valves,thus determining the amounts of fuel injected.

Now turning to FIG. 2, the engine speed sensor 50 comprises, in theillustrated embodiment of the invention, an annular ring, schematicallyindicated at 102, for mounting a circular array of appropriately spacedfluidic sensors, schematically indicated at 104 and numbered 1 through28 around the mounting ring. A semi-circular disc 106 is rotatedcoaxially with ring 102 in synchronism with the internal combustionengine via mechanical linkage 54 (FIG. 1). In practice, the disc 106 maybe linked to the engine cam shaft and thus is rotated at one-half theengine speed.

The fluidic sensors 104 may take a variety of forms, so long as theyhave the capability of developing digitized fluidic output signalsdepending upon whether or not the periphery of disc 106 is in opposedrelation thereto. Suitable fluidic sensors for use in the engine speedsensor 50 are back pressure sensors, such as shown in US. Pat. No.3,545,256. In the application of these specific fluidic sensors to theengine speed sensor 50, they operate to develop relatively high fluidicpressure or logical ONE output signals as long as the periphery of disc106 is in contiguous, opposed relation to their discharge orifices. Onthe other hand, when the periphery of disc 106 is not in opposedrelation to their discharge orifices, they develop relatively lowfluidic pressure or logical ZERO fluidic output signals.

The fluidic output signal developed by fluidic sensor No. 28 (alsodesignated by the letter A), together with the fluidic output signalsdeveloped by fluidic sensors Nos. 1 through 12 are supplied overseparate fluidic connections to fluidic logic 64. Although notspecifically shown, it will be understood that the fluidic outputsignals generated by fluidic sensors Nos. 7 through 12 are also suppliedto fluidic logic 66 (FIG. 1), together with the fluidic output signalsgenerated by fluidic sensors Nos. 13 through 19. The fluidic outputsignals developed by fluidic sensors Nos. 14 through 19 are alsosupplied to the fluidic logic circuitry 68, to-

gether with the fluid output signals developed by fluidic sensors Nos.20 through 26. Finally, the fluidic output signals developed by fluidicsensors 21 through 28 and 1 through 5 are also supplied to fluidic logic70.

As will be seen, the fluidic output signal developed by fluidic sensorNo. 28 (letter A) constitutes a synchronizing signal which is suppliedas an input to a pair of NOR gates 110 and 112, included in the fluidiclogic circuitry 64 detailed in FIG. 2. The output of fluidic NOR gate112 is connected through a fluidic delay line 113 as a second input tofluidic NOR gate 110, such that these two gates function as a monostablemultivibrator ofone-shot circuit 11 1. The fluidic output signalsdeveloped by fluidic sensors Nos. 1 through 12 are respectivelyconnected as one input to each of a plurality of two input fluidic NORgates, commonly indicated at 114 and numbered 1a through 12a, alsoincluded in logic circuitry 64.

It will be understood that the fluidic output signal generated byfluidic sensor No. 7 (letter B) is supplied as a synchronizing signal tofluidic logic circuitry 66, while the fluidic output signal from fluidicsensor No. 14 (letter C) is supplied as a synchronizing signal tofluidic logic circuitry 68 and the fluidic output signal developed byfluidic sensor No. 21 (letter D) is supplied as a synchronizing signalto fluidic logic circuitry 70. It will be noted that these fluidicsensors Nos. 28, 7, l4 and 21, also designated A through'D, are spaced90 apart, and thus the synchronizing signals generated by these fluidicsensors can conveniently be utilized to achieve the appropriate 90phasing between the fluid load signals generated by the four,identically constructed, fluidic logic circuits.

The mass air flow sensor 72, illustrated schematically in FIG. 2,comprises an annular member 120 for mounting a spaced array of fluidicsensors, indicated at 122 and numbered lb through 12b. These fluidicsensors may be of the same type used in the engine speed sensor 50. Asemi-circular disc 124 is mechanically linked, as diagrammaticallyindicated at 126, to a vacuum meter movement 128, which is coupled byfluid connection 72 to respond to the pressure at the throat of venturisection 76 included in the input end of the intake manifold 78. Theresponse of the vacuum meter movement 128 is effective to selectivelyangularly position disc 124, such that its periphery is in contiguous,opposed relation to the discharge orifices of an appropriate number offluidic sensors 122. As the mass air flow through venturi section 72 isincreased by throttle 79, the pressure at the venturi throat decreasesand the vacuum meter movement 128 responds by rotating disc 124 in theclockwise direction to increase the number of fluidic sensors 122opposed by the disc periphery. The fluidic output signals developed byfluidic sensors Nos. 1b through 12b are separately connected as thesecond input to each of the NOR gates Nos. 1a through 12a. Thus, thefluidic output signal from fluidic sensor No. 1 of the engine speedsensor is gated with the fluidic output signal from fluidic sensor No.1b of the mass air flow sensor in NOR gate No. 1a, and so on.

The outputs of NOR gates Nos. la through 40 are gated together in a fourinput NOR gate 130, while the outputs of NOR gate Nos. 5a through 8a aregated together in a NOR gate 132 and the outputs NOR gates Nos. 9athrough 12a are gated together in a NOR gate 134. The outputs of NORgates 130, 132 and 134 are complemented by NOR gates 136, 138 and 140and supplied as separate inputs to a three input NOR gate 142, Theoutput of this NOR gate is complemented in a NOR gate 144 and suppliedas one input to a three input NOR gate 146.

The output of NOR gate 110, of monostable multivibrator 111 is'gatedwith the output of NOR gate 146 in a two input NOR gate 148. The outputof this NOR gate is'supplied directly as a second input to NOR gate 146and is alsocomplemented in a NOR gate 150 and coupled through a fluidicdelay line 152 as the third input to NOR gate 146. In addition, theoutput of NOR gate 148 is complemented in NOR gate 154 and supplied to afluidic power amplifier 156, whose output constitutes the fluidic loadsignal supplied over fluidic connection 82 to control fuel injectionvalve 90. This valve may be any suitable type of conventionalairoperated valve which opens when a pulse of air is applied to it andcloses when the air pulse terminates. As will be seen, the fluidic loadsignal is in the form of a pulse, whose pulse interval determines thelength of time the valve element 90a of the fuel injection valve must beopen in order to inject the proper amount of fuel for mixture with airin the intake manifold 78, which miitture is then admitted throughintake valve 158 into cylinder 160 during the suction stroke of piston162 operating therein. Fluidic NOR gates are well know in the art andmay take a variety of forms. Package structures are available whichinclude a plurality of NOR logic elements, each having a four inputcapability. Such structures are shown in U.S. Pat. Nos. 3,512,558 and3,495,608. Fluidic power amplifier 156 simply amplifies the pulse outputfrom NOR gate 154 in order that the load signals at its output hassufficient drive'capability. A suitable fluidic power amplifier is shownin US. Pat. No. 3,507,295. I i

The operation of the fluid logic circuits in conjunction with the twosensors 50 and 72 will now be described. Assume that disc 106 of theengine speed sensor 50 is rotated in the clockwise direction'and thatits trailing edge is about to pass the discharge orifice of fluid sensorNo. 28, which has as one of its functions the generation of thesynchronizing signalfor fluidic logic circuit 64.Until the trailingedgeof disc 106 passes fluid sensor No. 28, its fluidic output signal isa logical ONE, which is effective to disable NOR gate 110 such that itsoutput is held to a logical ZERO. Similarly this logical ONE input iscomplemented by NOR gate 112 to a logical ZERO which is supplied throughfluidic delay line element 113 as an enabling input to NOR gate 110.Since the discharge orifices of fluidic sensors Nos. 1 through 12 areblocked by the periphery of disc 106, their resulting logical ONEoutputs are effective to disable each of the NOR gates 114. Theresulting logical ZERO outputs of these NOR gates fully qualify each ofthe NOR gates 130, 132 and 134, whose logical ONE outputs arecomplemented by NOR gates 136, 138 and 140 to fully qualify NOR gate142. its logical ONE output is complemented to a logical ZERO by NORgate 144 to enable NOR gate 146. However,

NOR gate 146, which operates in conjunction with NOR gates 148, 150 and154 as a variable length, fluidic pulse generatorl55. It will beunderstood that the provision of intermediate coincident NOR gates 130,132, 134 and 144 is necessitated solely by the fact that the particularfluidic NOR gates contemplated for use in the illustrated embodiment ofthe invention are limited to a maximum of four inputs. Thus, the numberof gates required to perform the requisite logic function on the outputsof the twelve NOR gates 114 is determined by the input numbercapabilities of the particular fluidic logic elements employed. It willalso be appreciated that the number of NOR gates 114 employed in eachfluidic logic circuit is a matter of choice, depending upon the pulselength resolution or variability desired of the load signal pulses. Thatis, by employing twelve fluidic snesors in each of the sensor 51) and72, to supply the fluidic inputs to each fluidic logic circuit, asillustrated herein, the load signal may be varied over twelve differentpulse lengths.

It will further be assumed that disc 124 of mass air flow sensor 72 isangularly oriented in response to the mass flow of air into the intakemanifold 78, as regulated by the throttle 79, such that the dischargeorifices of the first five fluidic sensors 122, Nos. 1b through 512, areblocked by the disc periphery, as illustrated in FIG. 2. Thus thefluidic output signals of these first five fluidic sensors are logicalONES, effective to disable the first five NOR gates, Nos. 1a through 5aof the NOR gate array 114. Since the discharge orifices of the remainingseven fluidic sensors 122 are not blocked by the periphery of disc 124,their fluidic outputs signals are logical ZEROES to qualify NOR gatesNos. 6a through 12a of the NOR gate array 114. it is understood that ifthe throttle 79 is open wider to increase the mass flow of air into theintake manifold 7%, disc 124 is rotated in the clockwise direction to anew angular position, such that an additional number of the NOR gates114 are disabled. Conversely, if the throttle 79 is closed, disc 124 isrotated in a counterclockwise direction to decrease the numberof NORgates 114 which are disabled by the fluidic output signals developed byfluidic sensors 122. j i

As the trailing edge of disc 106 in the engine speed sensor passesfluidic sensor No. 28, its fluidic output 6 signal goes from a logicalONE to a logical ZERO. The

since the output of NOR gate 148 normally sits at a logical ONE, theoutput of NOR gate 146, by virtue of the cross-coupling, is a logicalZERO to qualify the former for response to the output from multivibratorcircuit 111.

It is seen that the outputs of the twelve NOR gates 114 are effectivelyall gated together in order to control output of NOR gate 1 10 thus goesfrom a logical ZERO to a logical ONE. The output of NOR gate 148 thengoes from a logical ONE to a logical ZERO and is complemented to alogical ONE by NOR gate 154 to define the leading edge of the fluid loadsignal pulse, which is amplified in fluidic power amplifier 156 to drivethe .fuel injection valve to its open position. The injection of fuelinto the intake manifold 78 is thus initiated. With continued rotationof disc 106 in the engine speed sensor 50, its trailing edge passes insequence the fluidic sensors 104. The fluidic output signals of thesefluidic sensors successively go from a logical ONE to a logical ZERO to,in effect, sample or scan the NOR gate array 114 to determine the lowestnumbered NOR gate qualified by the fluidic output signals generated bythe mass air flow sensor 72. While this sampling is being carried out ata rate synchronized to the engine RPM, the fluidic load signal pulsecontinues at a logical ONE to maintain the fuel injection valve open andthus sustain the injection of fuel into the intake manifold.

Shortly after NOR gate 110 was fully enabled by the transition of thefluidic output signal from fluidic sensor No. 28 to a logical ZERO, theresulting logical ONE fluidic output from NOR gate 112, delayed byfluidic delay element 113 for approximately 3 milliseconds, disables NORgate 110. Thus the output of the monostable multivibrator 111 returns toits normal or stable state with its logical ZERO output serving toqualify NOR gate 148. However, by virtue of the cross coupling'betweenNOR gates 148 and 146, the initial transition of the output of theformer from a logical ONE to a logical ZERO, thereby defining theleading edge of the load signal pulse,.was effective to fully enable NORgate 146 and its resulting logical ONE output maintains NOR gate 148disabled to sustain the load signal pulse.

When the trailing edge of disc 106 passes fluidic sensor No. 6 in theengine speed sensor 50, the transition of its output signal from alogical ONE to a logical ZERO finds that NOR gate No. 6 in the NOR gatearray 114 is the lowest numbered gate which has been qualified by themass air flow sensor 72. Since the first five NOR gates weredisqualified by the mass air flow sensor, the preceding transitions ofthe fluidic output signals from fluidic sensors Nos. 1 through 5 fromlogical ONES to logical ZEROES had no effect on their fluidic outputsignals. However, when NOR gate No. 6 is sampled, both of its inputs arelogical ZEROES and its output goes to a logical ONE. NOR gate 132 isdisabled, and its logical ZERO output, as complemented by NOR gate 138,is effective to disable NOR gate 142. The output of this gate goes to alogical ZERO and is complemented to'a logical ONE by NOR gate 144 todisable NOR gate 146. The fluidic output of NOR gate 146 returns to itsnormal, logical ZERO level which is effective to fully enable NOR gate148. The output of this NOR gate goes from a logical ZERO to a logicalONE, thereby terminating the load signal pulse and effecting closure offuel injection valve 90.

If for some reason none of the NOR gates 114 were enabled so as toterminate the fluidic load signal pulse, it is automatically terminatedafter a predetermined length ofitime, for example, milliseconds, by theoutput of NOR gate 150 supplied through fluidic delay line element 152to the input of NOR gate 146. Specifically, on the leading edge of thefluidic load signal pulse, the output of NOR gate 150 goes from alogical ZERO to a logical ONE. The application of this logical ONEfluidic signal to NOR gate 146 is delayed for 20 milliseconds by fluidicdelay line element 152. Thus, if the fluidic load signal pulse is notterminated by a'logical ONE input from NOR gate 144, it is terminatedafter 20 milliseconds by the output from NOR gate 150. Thus, the maximumpulse length of the load signal pulse is 20 milliseconds-in theillustrated embodiment of the invention.

From the foregoing description, it is seen that for an engine speed of,for example 900 RPM, if the positions of consecutive fluidic sensors 104in the engine speed sensor 50 are 2.4 milliseconds apart and fluidicsensor No. 6b of the mass air flow sensor 72 is the lowest numberedfluidic' sensor providing an enabling, logical ZERO input to the NORgate array 114, the pulse length of the load signal is 6 X 2.4milliseconds or 14.4 milliseconds.

' It is understood that when the trailing edge of disc 106 in the enginespeed sensor passes fluidic sensor No. 7, the transition of its fluidicoutput signal from a logical ONE to a logical ZERO is used not only tosample NOR gate No. 7a in fluidic logic circuitry 64 but also to triggerthe multivibrator 111 in fluidic logic circuitry 66 to define theleading edge of the load signal pulse derived to control the fuelinjection valve associated with the cylinder or cylinders out of phasewith the cylinder or cylinders handled by fluidic logic circuitry 64.Similarly, fluidic sensor No. 14, away from fluidic sensor No. 28,delivers its logical ONE to logical ZERO fluidic output signaltransition to the NOR gate array 114 of fluidic logic circuitry 66 andalso triggers the multivibrator 111 in fluidic logic 68 to define theleading edge of the load signal pulse developed thereby. Also, thefluidic output signal from fluidic sensor No. 21 is used to sample theNOR gate array 114 in fluidic logic circuitry 68 and also to trigger themultivibrator ll 1 in the fluidic logic 70, thereby defining the leadingedge of the load signal pulse developed thereby. Finally, the fluidicoutput signal of fluidic sensor No. 28 is also used to sample the NORgate array 114 in fluidic logic circuitry 70, as well as to triggermultivibrator 111 in fluidic logic 64.

It will thus be seen that the objects set forth above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made in the above construction withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

Having described the invention, what is claimed as new and desired to besecured by Letters Patent is:

1. Apparatus for controlling a fuel injection valve-in a fuel injectionsystem-for an internal combustion engine, said apparatus comprising, incombination:

A. an engine speed sensor for deriving a first fluidic output indicativeof engine speed;

B. a mass air flow sensor for deriving a second fluidic outputindicative of the mass of air flow into the intake manifold of theengine, said second fluidic output comprising a plurality of discretedigitized second fluidic output signals, each of said digitized outputsignals corresponding to a different rate of mass of air flow into theintake manifold of the engine; and v C. fluidic circuitry for processingsaid first and second fluidic outputs to derive a fluidic load signalfor controlling the injection valve to admit a determined amount of fuelfor mixture with air and ultimate combustion in a cylinder of theengine.

2. The system defined in claim 1, wherein said engine speed sensorincludes means for generating said first fluidic output as a successionof first fluidic output signals at rate proportional to engine speed.

3. The apparatus defined in claim 1, wherein said load signal is in theform of a pulse to effect the opening of the injection valve to admitfuel for the duration of the pulse interval, said fluidic circuitryincluding first means for processing said first fluidic output tosynchronize the leading edge of said load signal pulse to the operatingcycle of the engine and second means for processing said first fluidicoutput in conjunction with said second fluidic output to terminate saidload signal pulse on the basis of the instantaneous engine load.

4. The apparatus defined in claim 1, wherein said engine speed sensorincludes means for generating said first fluidic output as asynchronizing output signal followed by a succession of first digitizedoutput signals generated at a rate proportional to engine speed, andsaid fluidic circuitry includes first logic means responsive to saidsynchronizing output signal for synchroniz ing the leading edge of saidload signal to the engine operating cycle and second logic. meansresponsive to said first digitized output signals and said seconddigitized output signals to terminate said load signal, whereby saidload signal is in the form of a pulse of a pulse length proportional toengine load for effecting the opening of the injection valve to admitfuel for the duration of said pulse.

The apparatus defined in claim 4, wherein said first logic meansincludes a fluidic pulse generator for generating said load signalpulse, said pulse generator being triggered on in response to saidsynchronizing output signal, and said second logic means includes anarray of fluidic coincident gating elements, each connected to receive adifferent one of said second digitized output signals and connected tobe sampled in predetermined sequence by said succession of said firstdigitized output signals, the first of said elements sampled in sequenceby said first digitized output signals found to be qualified by one ofsaid second digitized output signals deriving a fluidic output signalfor triggering said pulse generator off, thereby to define said fluidicload signal pulse interval.

6. The apparatus defined in claim 5, wherein said pulse generatorincludes means for automatically triggering itself off after apredetermined time interval in the event it is not triggered off by saidfluidic output derived from one of said gating elements.

7. The apparatus defined in claim 5, wherein said pulse generatorincludes a first fluidic gating element having a first input connectedto respond to said synchronizing output signal, a second input and anoutput on which said load signal pulse appears; a second flu idic gatingelement having a first input connected to the output of said firstgating element, a second input connected to receive said output signalderived by said coincident gating element array, a third input, and anoutput connected to said second input of said first gating element; athird fluidic gating element for complementing the output of saidfirstgating element; and a fluidic delay lineelement connecting saidthird gatingelement to said third input of said second gating element.

8. The apparatus defined in claim 7, wherein said fluidic circuitryfurther includes a fluidic monostable multivibrator circuit connected tobe triggered to generate a fluidic pulse of fixed length by saidsynchronizing output signal, said fluidic pulse being coupled to saidfirst input of said first gating element.

9. The apparatus defined in claim 5, wherein said engine speed sensorcomprises an array of first fluidic sen- I sors and means operating insynchronism with the engine to actuate said first fluidic sensors insequence to generate said synchronizing output signal and saidsuccession of first digitized output signals.

10. The apparatus definedin claim 9, wherein said mass air flow sensorcomprises an array of second fluidic sensors and means positionable inaccordance with the mass of air flow into the intake manifold to actuatea selected number of said second. fluidic sensors, whereby to generatesaid second digitized output signals.

llll. Apparatus for contolling the various fuel injection valves in afuel injection system fora multicylinder internal combustion engine,said apparatus comprising, in combination:

A. an engine speed sensor for deriving a plurality of phased firstfluidic outputs, each indicative of engine speed;

B. a mass air flow sensor for deriving a second fluidic outputindicative of the mass of air flow into the intake manifold of theengine, said second fluidic output comprising a plurality of discretedigitized second fluidic output signals, each of said digitized outputsignals corresponding to a differentrate of mass of air flow into theintake manifold of the engine; and

C. plural fluidic circuits for processing different ones of said firstfluidic outputs in conjunction with said second fluidic output to derivephased fluidic load signals for separately controlling the various fuelinjection valves.

12. The apparatus defined in claim ll, wherein said load signals areeach in the form of a pulse to effect the opening of different ones ofthe injection valves to admit fuel for the durations of the various loadsignal pulse intervals, said fluidic circuits each including first meansfor processing a different one of said first fluidic outputs tosynchronize the leading edge. of a different one of said load signalpulses to the operating cycle of the engine and second means forprocessing said one first fluidic output in conjunction with said secondfluidic output to terminate said one load signal pulse on the basis ofthe instantaneous engine load.

I 13. The apparatus defined in claim 11, wherein said engine speedsensor includes means for generating each of said first fluidic outputsas a synchronizing output signal followed by a succession of firstdigitized output signals generated at a rate proportional to enginespeed, said synchronizing output signals being phased relative to eachother, and each said fluidic circuit includes first logic meansresponsive to a different one of said synchronizing output signals forsynchronizing the leading edge of a different one of said load signalsto the engine operating cycle and second logic means responsive to thesuccession of first digitized output signals succeeding said onesynchronizing output signal and said second digitized output. signals toterminate said one load signal, whereby each of said load signals is inthe form of a pulse of apulse length proportional to engine load foreffecting the opening of the various injection valves to admit fuel forthe durations of said load signal pulses.

14. The apparatus defined in claim 13, wherein said first logic means ofeach said fluidic circuit includes a fluidic pulse generator forgenerating one of said load signals, said pulse generator of each saidfluidic circuit being triggered on in response to a different one ofsaid synchronizing output signals to define the leading edge of adifferent one of said load signal pulses, and said second logic means ofeach said fluidic circuit includes an array of fluidic coincident'gatingelements, each connected to receive a different one of said seconddigitized output signals and connected to be sampled in predeterminedsequence by the succession of said first digitized output signalsimmediately succeeding said one synchronizing output signal, the firstof said elements sampled in sequence by said first digitized outputsignals found to be qualified by one of said second digitized outputsignals deriving a fluidic output signal for triggering said pulsegenerator off, thereby to define the pulse interval of said one fluidicload signal pulse.

15. The apparatus defined in claim 14, wherein each said pulse generatorincludes means for automatically triggering itself off to terminate saidone load signal pulse in the event it is not triggered off by saidfluidic output derived from one of said gating elements.

16. The apparatus defined in claim 14, wherein said engine speed sensorcomprises an array of first fluidic sensors and means operating insynchronism with the engine speed to actuate said first fluidic sensorsin sequence to generate said relative phased synchronizing outputsignals and said successions of first digitized output signals.

17. The apparatus defined in claim 16, wherein certain ones of saidfirst fluidic sensors are connected to supply said synchronizing outputsignal to one of said fiuidic circuits and a first digitized outputsignal to a nals.

1. Apparatus for controlling a fuel injection valve in a fuel injectionsystem for an internal combustion engine, said apparatus comprising, incombination: A. an engine speed sensor for deriving a first fluidicoutput indicative of engine speed; B. a mass air flow sensor forderiving a second fluidic output indicative of the mass of air flow intothe intake manifold of the engine, said second fluidic output comprisinga plurality Of discrete digitized second fluidic output signals, each ofsaid digitized output signals corresponding to a different rate of massof air flow into the intake manifold of the engine; and C. fluidiccircuitry for processing said first and second fluidic outputs to derivea fluidic load signal for controlling the injection valve to admit adetermined amount of fuel for mixture with air and ultimate combustionin a cylinder of the engine.
 2. The system defined in claim 1, whereinsaid engine speed sensor includes means for generating said firstfluidic output as a succession of first fluidic output signals at rateproportional to engine speed.
 3. The apparatus defined in claim 1,wherein said load signal is in the form of a pulse to effect the openingof the injection valve to admit fuel for the duration of the pulseinterval, said fluidic circuitry including first means for processingsaid first fluidic output to synchronize the leading edge of said loadsignal pulse to the operating cycle of the engine and second means forprocessing said first fluidic output in conjunction with said secondfluidic output to terminate said load signal pulse on the basis of theinstantaneous engine load.
 4. The apparatus defined in claim 1, whereinsaid engine speed sensor includes means for generating said firstfluidic output as a synchronizing output signal followed by a successionof first digitized output signals generated at a rate proportional toengine speed, and said fluidic circuitry includes first logic meansresponsive to said synchronizing output signal for synchronizing theleading edge of said load signal to the engine operating cycle andsecond logic means responsive to said first digitized output signals andsaid second digitized output signals to terminate said load signal,whereby said load signal is in the form of a pulse of a pulse lengthproportional to engine load for effecting the opening of the injectionvalve to admit fuel for the duration of said pulse.
 5. The apparatusdefined in claim 4, wherein said first logic means includes a fluidicpulse generator for generating said load signal pulse, said pulsegenerator being triggered on in response to said synchronizing outputsignal, and said second logic means includes an array of fluidiccoincident gating elements, each connected to receive a different one ofsaid second digitized output signals and connected to be sampled inpredetermined sequence by said succession of said first digitized outputsignals, the first of said elements sampled in sequence by said firstdigitized output signals found to be qualified by one of said seconddigitized output signals deriving a fluidic output signal for triggeringsaid pulse generator off, thereby to define said fluidic load signalpulse interval.
 6. The apparatus defined in claim 5, wherein said pulsegenerator includes means for automatically triggering itself off after apredetermined time interval in the event it is not triggered off by saidfluidic output derived from one of said gating elements.
 7. Theapparatus defined in claim 5, wherein said pulse generator includes afirst fluidic gating element having a first input connected to respondto said synchronizing output signal, a second input and an output onwhich said load signal pulse appears; a second fluidic gating elementhaving a first input connected to the output of said first gatingelement, a second input connected to receive said output signal derivedby said coincident gating element array, a third input, and an outputconnected to said second input of said first gating element; a thirdfluidic gating element for complementing the output of said first gatingelement; and a fluidic delay line element connecting said third gatingelement to said third input of said second gating element.
 8. Theapparatus defined in claim 7, wherein said fluidic circuitry furtherincludes a fluidic monostable multivibrator circuit connected to betriggered to generate a fluidic pulse of fixed Length by saidsynchronizing output signal, said fluidic pulse being coupled to saidfirst input of said first gating element.
 9. The apparatus defined inclaim 5, wherein said engine speed sensor comprises an array of firstfluidic sensors and means operating in synchronism with the engine toactuate said first fluidic sensors in sequence to generate saidsynchronizing output signal and said succession of first digitizedoutput signals.
 10. The apparatus defined in claim 9, wherein said massair flow sensor comprises an array of second fluidic sensors and meanspositionable in accordance with the mass of air flow into the intakemanifold to actuate a selected number of said second fluidic sensors,whereby to generate said second digitized output signals.
 11. Apparatusfor contolling the various fuel injection valves in a fuel injectionsystem for a multicylinder internal combustion engine, said apparatuscomprising, in combination: A. an engine speed sensor for deriving aplurality of phased first fluidic outputs, each indicative of enginespeed; B. a mass air flow sensor for deriving a second fluidic outputindicative of the mass of air flow into the intake manifold of theengine, said second fluidic output comprising a plurality of discretedigitized second fluidic output signals, each of said digitized outputsignals corresponding to a different rate of mass of air flow into theintake manifold of the engine; and C. plural fluidic circuits forprocessing different ones of said first fluidic outputs in conjunctionwith said second fluidic output to derive phased fluidic load signalsfor separately controlling the various fuel injection valves.
 12. Theapparatus defined in claim 11, wherein said load signals are each in theform of a pulse to effect the opening of different ones of the injectionvalves to admit fuel for the durations of the various load signal pulseintervals, said fluidic circuits each including first means forprocessing a different one of said first fluidic outputs to synchronizethe leading edge of a different one of said load signal pulses to theoperating cycle of the engine and second means for processing said onefirst fluidic output in conjunction with said second fluidic output toterminate said one load signal pulse on the basis of the instantaneousengine load.
 13. The apparatus defined in claim 11, wherein said enginespeed sensor includes means for generating each of said first fluidicoutputs as a synchronizing output signal followed by a succession offirst digitized output signals generated at a rate proportional toengine speed, said synchronizing output signals being phased relative toeach other, and each said fluidic circuit includes first logic meansresponsive to a different one of said synchronizing output signals forsynchronizing the leading edge of a different one of said load signalsto the engine operating cycle and second logic means responsive to thesuccession of first digitized output signals succeeding said onesynchronizing output signal and said second digitized output signals toterminate said one load signal, whereby each of said load signals is inthe form of a pulse of a pulse length proportional to engine load foreffecting the opening of the various injection valves to admit fuel forthe durations of said load signal pulses.
 14. The apparatus defined inclaim 13, wherein said first logic means of each said fluidic circuitincludes a fluidic pulse generator for generating one of said loadsignals, said pulse generator of each said fluidic circuit beingtriggered on in response to a different one of said synchronizing outputsignals to define the leading edge of a different one of said loadsignal pulses, and said second logic means of each said fluidic circuitincludes an array of fluidic coincident gating elements, each connectedto receive a different one of said second digitized output signals andconnected to be sampled in predetermined sequence by the succession ofsaid fiRst digitized output signals immediately succeeding said onesynchronizing output signal, the first of said elements sampled insequence by said first digitized output signals found to be qualified byone of said second digitized output signals deriving a fluidic outputsignal for triggering said pulse generator off, thereby to define thepulse interval of said one fluidic load signal pulse.
 15. The apparatusdefined in claim 14, wherein each said pulse generator includes meansfor automatically triggering itself off to terminate said one loadsignal pulse in the event it is not triggered off by said fluidic outputderived from one of said gating elements.
 16. The apparatus defined inclaim 14, wherein said engine speed sensor comprises an array of firstfluidic sensors and means operating in synchronism with the engine speedto actuate said first fluidic sensors in sequence to generate saidrelative phased synchronizing output signals and said successions offirst digitized output signals.
 17. The apparatus defined in claim 16,wherein certain ones of said first fluidic sensors are connected tosupply said synchronizing output signal to one of said fluidic circuitsand a first digitized output signal to a different one of said fluidiccircuits.
 18. The apparatus defined in claim 17, wherein others of saidfirst fluidic sensors are connected to supply first digitized outputsignals to two different fluidic circuits.
 19. The apparatus defined inclaim 16, wherein said mass air flow sensor comprises an array of secondfluidic sensors and means positionable in accordance with the mass ofair flow into the intake manifold to actuate a selected number of saidsecond fluidic sensors, whereby to generate said second digitized outputsignals.